Showing papers by "Shriners Hospitals for Children - Galveston published in 2006"

The use of beta-adrenergic blockade in preventing trauma-induced hepatomegaly.

Abstract: Catecholamine-mediated hypermetabolism,1–3 lipolysis4, and fatty liver5–7 are striking characteristics of the stress response to a major thermal injury. The deposition of fat in the liver is a common pathologic finding, as is liver size, which may vary 2- to 3-fold.6,8–11 Hepatic fat accumulation (fatty liver) may be due to a high rate of peripheral lipolysis coupled with a lack of increased fat oxidation.12,13 The extent to which triglycerides (TGs) are produced and the capacity of the liver to excrete them into the blood via very low density lipoproteins (VLDLs) is important in determining net fat accumulation in the liver. It has previously been shown that plasma free fatty acid (FFA) is the primary precursor for hepatic TG synthesis.14 The increase in basal lipolysis in burn patients is caused by excessive catecholamine production, which can be diminished by beta-adrenergic blockade with propranolol.12,13,15 Acute use of β-blocking agents precipitously decreases the rate of release or appearance of plasma FFAs, indicating the important role that preexisting sympathetic activity plays in the mobilization of FFAs.4 We recently found in an acute study that β-blockade decreased TG accumulation in the liver by decreasing the supply of FFAs to the liver.16 The effect of chronic treatment with β-blockade on hepatic TG accumulation has not been assessed. Cardiac output and heart rate have been shown to be higher in the dynamic phase of a thermal injury than most other hyperdynamic conditions.3 In the hypermetabolic phase of burn recovery, cardiac dysfunction contributes significantly to mortality.7,17 Beta-adrenergic blockade has been used with success in pathologic states produced by excessive quantities of endogenous or exogenous thyroid hormone or catecholamines by decreasing the myocardial workload.18,19 We have previously shown that, after adrenalectomy or catecholamine depletion by chronic reserpine administration, rats given a 50% total body surface area (TBSA) burn had lower metabolic rates and increased mortality.20 Wilmore et al1 have shown that the dose of β-blocking agent required for decreasing heart work in patients with major burns also decreases metabolic rate, core and skin temperatures, and may be beneficial in maintaining the responsiveness of subcellular enzymes to catecholamine control.12 The purpose of this study was to test the hypothesis that propranolol, given to children with severe thermal injuries, could be beneficial by attenuating peripheral lipolysis, portal blood flow, and hepatomegaly.

Quantification of protein metabolism in vivo for skin, wound, and muscle in severe burn patients.

Abstract: Background: In response to injury, muscle catabolism can be extensive, and in theory, the wound consumes amino acids to support healing. The purpose of this study is to assess a technique by which in vivo protein kinetics of muscle, wound, and normal skin can be quantified in burn-injured patients. Methods: Study protocol consisting of infusion of d5 phenylalanine; biopsies of skeletal muscle, skin, and donor-site wound on the leg; quantification of blood flow to total leg, wound, and skin; and sequential blood sampling from the femoral artery and vein. Five-compartment modeling was used to quantify the rates of protein synthesis, breakdown, and phenylalanine transport between muscle, wound, and skin. Results: The study results demonstrated a net release of phenylalanine from muscle yet a net consumption of phenylalanine by the wound. Compared with skin, the wound had a substantially increased rate of protein synthesis and a reduced rate of protein breakdown (p < .01). Transport rates into and out of musc...

CCL2 as a trigger of manifestations of compensatory anti-inflammatory response syndrome in mice with severe systemic inflammatory response syndrome

Abstract: Patients with compensatory anti-inflammatory response syndrome (CARS) are at a higher risk for infection with various opportunistic pathogens. CARS develops commonly in association with the manifestation of systemic inflammatory response syndrome (SIRS). In the present study, the role of SIRS-associated soluble factors on the CARS development was examined in mice with pancreatitis, a carrier of typical SIRS. Following the production of SIRS-related cytokines [tumor necrosis factor alpha and interleukin (IL)-1beta], CC chemokine ligand 2 (CCL2), IL-4, and IL-10 (typical CARS cytokines) were detected in the sera of mice with pancreatitis. CCL2 has been described as an essential chemokine for the T helper cell type 2 manifestation. CARS effector cells (cells with an ability to produce IL-4 and IL-10) were not generated from normal T cells after stimulation with SIRS-related cytokines. However, these cells were generated from normal T cells after cultivation with peripheral blood neutrophils (PMN) from SIRS mice in a dual-chamber transwell. Normal T cells did not convert to CARS effector cells after transwell cultures with PMN from normal mice. CCL2 was detected in culture fluids of PMN from SIRS mice, and PMN from normal mice did not produce CCL2 into their culture fluids. CARS effector cells did not appear in PMN-depleted SIRS mice or SIRS mice treated with anti-CCL2 monoclonal antibody, and these cells were demonstrated in PMN-depleted SIRS mice after treatment with recombinant murine CCL2. These results indicate that CCL2 produced by PMN from SIRS mice is an active molecule on the SIRS-associated CARS manifestation.

Differential effects of dietary intake of palmitic acid and oleic acid on oxygen consumption during and after exercise.

Abstract: Our previous studies suggest that diets varying in palmitic acid (PA) and oleic acid (OA) content may affect energy expenditure and fat oxidation differentially. We hypothesized that, compared with a high-OA diet, a high-PA diet would lead to lower oxygen consumption during exercise and lower excess postexercise oxygen consumption (EPOC). Adults were randomized to 1 of 2 liquid diets (28 days): HI PA (fat, 40% of energy; PA, 16.8%; OA, 16.4%) (n = 10) or HI OA (fat, 40%; PA, 1.7%; OA, 31.4%) (n = 9). On day 29, the rates of oxygen consumption (V o(2)) and carbon dioxide production were measured during and for 270 minutes after 80 minutes of cycling (60% V o(2 peak)). There was no group difference (HI OA vs HI PA, mean +/- SEM) in fat-free mass (53.8 +/- 4.7 vs 56.9 +/- 3.0 kg), V o(2 peak) (40.7 +/- 2.3 vs 36.6 +/- 3.2 mL/kg per minute), and work during exercise (101 +/- 12 vs 101 +/- 10 W). V o(2) (L/min) during exercise (1.99 +/- 0.22 vs 1.85 +/- 0.19) was significantly different (P = .05) only when corrected for fat-free mass, with which it significantly correlated (r = 0.86; P < .001). During 60 to 270 minutes postexercise, the average EPOC was 9.7% +/- 4.9% of preexercise V o(2) in OA, whereas there was no EPOC present in PA (P = .06 between diets). In conclusion, a high-PA diet appears to lower V o(2) during and after exercise compared with a high-OA diet.

Can burn centers evacuate in response to disasters

Abstract: On August 29, 2005, the Gulf Coast was hit by Hurricane Katrina, a category 4 storm. The storm was responsible for more than 1000 deaths and the displacement of hundreds of thousands of people. Hospitals in the city of New Orleans evacuated because of the complete collapse of infrastructure. This event influenced the decisions and actions taken to protect patients, families, and staff of a 30-bed pediatric burn center in the projected path of a second catastrophic hurricane 3 weeks later. Approximately 80 hours before projected landfall, the local government announced that a mandatory evacuation of the community surrounding the burn center would occur. A coordinated decision was made by administration, nursing, and medical staff to cancel upcoming clinics and elective surgery and to evacuate all 14 inpatients, 52 outpatients, and 66 guardians to other facilities. The evacuation plan was successfully completed in 32 hours. The eye wall of the hurricane passed 65 miles east of the burn center. No significant damage to the physical plant was noted. Repopulation of the hospital by patients and acceptance of new acute burn referrals began approximately 40 hours after the local government permitted the population to return to the area. No morbidity or mortality was attributed to the evacuation. Emergent evacuation of threatened burn centers can be safely accomplished with adequate prior planning of evacuation sites, and modes of transportation. An established communication command center plays a key role in this process.

Comparison of carbon monoxide (CO) single breath pulmonary diffusing capacity with non-rebreathing, open-circuit CO pulmonary diffusing capacity in healthy children.

Abstract: Introduction The standard technique for assessing pulmonary diffusing capacity of the lungs (DL) for carbon monoxide (CO) is the single breath (SB) technique. SB_DLco in children can be problematic because it requires a vital capacity >1.5 L. We have developed an open-circuit technique (OC), which uses the wash-in of CO over a series of 8–10 normal breaths that does not require rebreathing. In this study, we compared the SB_DLco against the OC_DLco. Methods Nineteen healthy children between 7 and 18 years performed SB_DLco and OC_DLco tests. The mean SB_DLco was significantly larger than the mean OC_DLco. The mean difference OC_DLco minus SB_ DLco was: −2.92 ± 4.21 ml/min/mm Hg, though the difference was negatively correlated with the mean of the two (r = 0.73). The lower mean OC_DLco was in part due to lower lung volume (as measured by alveolar volume (VA)) during the maneuver. In both groups there was a positive correlation between VA and DLco, and the mean VA was −2.17 ± 1.07 L lower using OC compared to SB. The difference was again negatively correlated with the mean (r = 0.82). The mean OC minus SB difference in DLco/VA was: 6.06 ± 1.98 ml/min/mm Hg/L, though this difference was positively correlated with the mean, r = 0.76. Conclusions We found a good correlation between both techniques for DLco, VA, and DLco/VA. The OC offers the advantage of minimal subject cooperation, and may be preferable to use in children. Pediatr Pulmonol. 2006, 41:1095–1102. © 2006 Wiley-Liss, Inc.

Metabolic changes following major burn injury: How to improve outcome

Abstract: The changes in patient metabolism following a major burn may be seen for more than 12 months after the initial injury. The ensuing period of hypermetabolism and catabolism post-burn leads to impaired immune function, decreased wound healing, erosion of lean body mass, and hinders rehabilitative efforts delaying reintegration into normal society. The typical changes in metabolism are the development of a hyperdynamic circulation [1], increased body temperature [2], increased protein catabolism with peripheral protein wasting [3], increased lipolysis leading to fatty infiltration of the liver [4], increased glycolysis and futile substrate cycling 5. These changes are responsible for much of the morbidity and mortality seen with such an injury and as such are important targets for available treatments including: early excision and grafting; aggressive treatment of sepsis, early commencement of high protein, high carbohydrate enteral feeding, elevation of the immediate environmental temperature to 31.5°C (±0.7°C); and early institution of an aerobic resistive exercise program. Several pharmacotherapeutic options are also available to further reduce erosion of lean body mass; these include anabolic agents such as recombinant human growth hormone, insulin, oxandrolone and beta-blockade with propranolol. This chapter will discuss the metabolic changes seen following a major burn and how different treatment options affect outcome.

Role for IL-4 nonproducing NKT cells in CC-chemokine ligand 2-induced Th2 cell generation.

Abstract: NKT cells from C57Bl/6 mice are known to be the initial cellular source of IL-4 that acts as a trigger for Th2 cell differentiation. CC-chemokine ligand 2 (CCL2) has been described as an initial stimulator of IL-4 production by these cells; however, IL-4 was not produced by NKT cells from BALB/c mice even when Th2 cell responses were established in these mice. In this study, we found a new pathway for CCL2-associated Th2 cell generation in BALB/c mice. Splenic T cells from BALB/c mice produced IL-4 in response to CCL2 stimulation. However, IL-4 production was not seen in cultures of splenic T cells from CD1-/- mice (BALB/c origin), whereas, in the presence of CCL2, splenic T cells from CD1-/- mice produced IL-4 when NKT cells from wild-type mice were added. CCL2 induced IL-4 in cultures of NKT cells cocultured with naive T cells, but IL-4 was not produced by these cells cultured separately with CCL2. Interestingly, IL-4 was produced by naive T cells cocultured with NKT cells that were previously treated with CCL2 (CCL2-NKT cells). In addition, IL-4 was produced by naive T cells supplemented with a culture supernatant of CCL2-NKT cells. These results indicate that, through the production of a soluble factor(s) other than IL-4, NKT cells play a role in the CCL2-associated generation of Th2 cells.

Regional Sensory Nerve Blocks of the Scalp Decrease the Incidence of Post-Operative Nausea and Vomiting in Reconstructive Burn Children: A Pilot Study: 198.

Abstract: Introduction: Surgical procedures involving the scalp are associated with relatively intense postoperative pain and a high incidence of postoperative nausea and vomiting. The purpose of this study was to evaluated the use of regional scalp sensory blockade as a method to improve postoperative analgesia and control nausea and vomiting in children requiring scalp surgery. Methods: Using a retrospective chart review between August 2004–2005 62 isolated procedures of the scalp were reviewed. Thirty children had received a scalp block and 32 did not. Ward nurses administering post-operative p.r.n. doses of analgesics or antiemetics were not advised of scalp blocks performed or their potential for improving postoperative nausea or vomiting and pain control. Data collected from the twenty-four hour postoperative period included patient demographics, scalp block description, intraoperative analgesic and prophylactic antiemetic administration, frequency of recovery room and ward administration of rescue doses of analgesics, antiemetics, and frequency of nausea and vomiting. Results: Results showed decreased frequency of analgesic and antiemetic drug requirement during the twenty-four hour postoperative period after scalp surgery in the patients who received regional scalp block. The incidence of nausea and vomiting was 16.7% (5 of 30) in patients who received a scalp block and 56.3% (18 of 32) without block; statistically significant with a p-value of .001. The reported incidence of pain was also lower in the block group regardless of procedure, 30% (9 of 30) vs. 53.1% (17 of 31), but was not statistically significant at the 0.05 level (p .065). There were no complications associated with the scalp blocks. Conclusions: Regional scalp sensory blockade significantly decreases postoperative nausea and vomiting after scalp surgery. Improved analgesia did not reach statistical significance, although there was a strong suggestion that pain was decreased in the block group. Postoperative nausea and vomiting may be reduced by a combination of reduced scalp discomfort and reduced exposure to opiates. An ongoing randomized, prospective study, with a larger group size may demonstrate statistically significant improvement in analgesia.